Hi, On 13/12/17 16:04, Auger Eric wrote: > Hi Peter, > > On 13/12/17 07:49, Peter Xu wrote: >> On Tue, Dec 12, 2017 at 12:59:39PM -0700, Alex Williamson wrote: >>> The vfio_info_add_capability() helper requires the caller to pass a >>> capability ID, which it then uses to fill in header fields, assuming >>> hard coded versions. This makes for an awkward and rigid interface. >>> The only thing we want this helper to do is allocate sufficient >>> space in the caps buffer and chain this capability into the list. >>> Reduce it to that simple task. >>> >>> Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx> >> >> Reviewed-by: Peter Xu <peterx@xxxxxxxxxx> >> >> Though during review I had a question related to the function >> msix_sparse_mmap_cap(): Is it possible that one PCI device BAR is very >> small (e.g., 4K) that only contains the MSI-X table (and another small >> PBA area)? If so, should we just mark that region unmappable instead >> of setting vfio_region_info_cap_sparse_mmap.nr_areas to 1 in >> msix_sparse_mmap_cap()? >> >> /* If MSI-X table is aligned to the start or end, only one area */ >> if (((vdev->msix_offset & PAGE_MASK) == 0) || >> (PAGE_ALIGN(vdev->msix_offset + vdev->msix_size) >= end)) >> nr_areas = 1; >> >> Thanks, >> > if I understand the code correctly, if the MSI-X table exactly matches > the BAR, a sparse mmap region is reported with offset/size = 0. Is that > correct? > > Thanks > > Eric > looks fixed by [RFC PATCH kernel] vfio-pci: Fix sparse capability when no parts of MSIX BAR can be mapped Sorry for the noise. Thanks Eric
